Hexanebisdibutylamide as plasticizer for butadiene-acrylonitrile copolymer



Patented June 28, 1949 LETS .O FFICE 2-,474,776 HEXANEBISDIBUTYLAMIDE .AS BI JASFII- CIZ-ER FOR BUTADIENE-ACRYLONL TRILE GQPOLYMER Arthur: Gampbell, Terre 'lHautc; z'Ind., .assignor to Commercial Solvents :Corporaltion, Terre Haute, Ind., a corporation of Maryland No Drawing. Application March22; 1945',

Serial No. 584245 1 Claim. (Cl. 260-326) UT E 1 2 This invention relates to plasticizing of 1,3- A convenient method for evaluating the efbutadiene-acrylonitrile copolymer with hexanefectiveness of a substance as a plasticizer combisdibutylamide. prises milling the substance in a standard rubber In the manufacture and compounding of rubformula on a conventional rubber mill, and then her and synthetic rubber, it is necessary to bring 5 measuring the extrusion time at various presthe compound into a plastic state so that pigsures in an extrusion plastometer, for example, ments, fillers, and the like can be incorporated in an instrument and according to a method therein, and so that the product can be molded similar to that described by J. H. Dillon in Rubinto the desired shape before vulcanizing. In the ber Chemistry and Technology, vol. 9, pp. 496- case of natural rubber, simple heating by the 501 (July 1936). In order to evaluate the effect friction of milling on a roller mill induces the of the plasticizer on the tensile and elongation necessary degree of plasticity for these purposes. properties of the elastomer, samples of the sheet The so-called synthetic rubbers or synthetic are tested for these factors in the standard Scott elastomers on the other hand do not respond tensile tester. easily to milling treatment and often become Tensile, elon at on, and extrusion values as hard and brittle or crumble when subjected to measured y h n tr above r f rr su h illi It is, therefore e ti l t dd t were run on several representative amides includmany of the synthetic elastomers sgftening 01' ing the hexanebisdibutylamide 0f the present inplasticizing agents to facilitate satisfactory millventiening d forming operations The plasticizer was added in each case in the t is desirable t t Such ofteners t only indicated amount to the standard formula given plasticize the elastomer, but that they shall not below, and milled into the Stock in the convenseriously decrease the tensile strength and tlonal mannerstretching capacities of the plasticized material.

I have found that while many of the alkane- TEST COMPOSITION bisdialkylamides are excellent plasticizers for Parts y e t synthetic elastomers, hexanebisdibutylamide pro- BPtad1e{1e"acry1n1tYi1e copolymer 1 duces surprisingly better results than any of the Z1110 e 5 other compounds of this class which have been steallc 1 tested in plasticizing the copolymer of 1,3-buta- Benzothlazyl dlsulfide 1.5 diene and acrylonitrile. This copolymer is one of sulfur 1.5 the more difiicult of the synthetic elastomers to on 50 plasticize. Hexanebisdibutylamide imparts to Plastlclzel' 30 this copolymer beneficial softening properties without appreciably lowering to the tensile 9- strength and while increasing the elongation at After milling, part f each Sample was break of the resultmg composltlonjected to tensile and elongation tests, part was Hexanebi d b y e y be p p for tested in the extrusion plastometer with the resexample, by the following procedure: One mole ults i e bel w; of an ester of adipic acid is mixed in a distilla- 40 tion apparatus with two moles of dibutyl amine Table and heated until two moles of water have been eliminated. This water of reaction can be re- Exfirusim Time Tensile in Seconds moved in any suitable known manner, for ex strenqth Elong. at

ample by azeotropic distillation with a solvent Plastlme at Bre ak. 523% such as benzene. The product remains in the p 5% 7% distillation flask, and may be recovered and used as a plasticizer without further purification or it may be further purified by distillation, crystalg gggg tfigggg gfig g 31%? lization, or other appropriate method. e b ty igla. 2,270 41 The amount of plasticizer utilized will vary ggg fifgg gtfgflfgg gg;

with the degree of softness desired. Hexanebis- Dibutyl phthalete dibutylamide can be employed in a wide range of Tr i'i eg 'r5135515551555 2'980 19 proportions, and preferably within the range of trel) 2,540 395 0 35 concentrations varying from about ten to fortyfive parts by Weight of plasticizer for each In the above table, areduction in extrusion time parts by weight of copolymer. indicates an increase in plasticity, that is, the

more plastic the composition the more rapidly will it extrude, ata given pressure. It will be observed, that while all of the alkanebisdibutylamides tested produce a plasticizing effect on the copolymer the results produced by hexanebisdibiitylamide are outstanding. The plasticizing eiTect of this compound is approximately double that produced by the dibutyl phthalate control and about 3 times that of the closest alkanebisdibutylamide. The hexanebisdibutylamide increases substantlally the elongation at break of the unplasticized composition while increasing its tensile strength to only a trifling extent.

While the above describes the preferred embodiments of my invention, it is to be understood that departures may be made therefrom within the scope of the specification and claim.

5 tively plasticize said copolymer of hxanebisdibutylamide. W

ARTHUR. W. CAMPBELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 15 2,325,947 Garvey Aug. 3, 1943 2,339,056 Craver Jan. 11, 1944 

